Cervical cancer is a public health problem in Honduras. Cytology-based screening has failed in reducing cervical cancer rates in the country, and moving towards HPV primary screening is under evaluation. The ESTAMPA study aims to evaluate triage techniques for HPV positive women aged 30-64 years within an HPV-based screening programme. One of these techniques is the OncoE6 test, a qualitative test that detects levels of E6 oncoprotein expressed by HPV types 16 and 18. The test is robust, simple, fast (2.5 hours) and not very costly making it very promising for low-resource settings. We evaluate the performance of the OncoE6 test using samples from women in the ESTAMPA study, supplemented with samples from a referral population.
Cervical samples were collected from two different groups of women: 155 attending HPV-screening in the ESTAMPA study (screening group) and 41 attending colposcopy after HSIL cytology (referral group). Samples were tested blindly with Hybrid Capture II (hc2), the LiPA (Genotyping kit HPV GP, version 2, primers GP5+/GP6+) for genotyping and the OncoE6 test. HPV positive women in the ESTAMPA group and all the HSIL’s underwent colposcopy and biopsies were collected from visualised lesions and interpreted by a local pathologist. Estimates of sensitivity and specificity with corresponding 95% confidence intervals (95CI) for detection of cervical intraepithelial neoplasia grade 2 or worse lesions (CIN2+) of the OncoE6 test were obtained.
Ninety five women tested positive for HPV: 93 in both hc2 and LiPA and two only in LiPA. Twenty-one women tested positive for HPV16 and nine for HPV18 oncoproteins using the OncoE6 test. A total of seven CIN2’s, 6 CIN3’s and 31 cancers were diagnosed. Two CIN2’s and one cancer were detected in women in the screening group; all other cases were diagnosed in the referral group. The OncoE6 test was positive in all CIN2+ associated to HPV16/18 (three CIN2, four CIN3 and 19 cancers), in one cancer that tested negative in all other tests, and in three women with no high-grade disease. The sensitivity of the OncoE6 was 61.4% (95CI:45.5%-75.6%) for detection of CIN2+ and 100% (94.3-100) for CIN2+ associated to HPV 16 or HPV 18; the specificity for less than CIN2 was 98% (95CI:94.3%-99.6%).
The OncoE6 test showed high concordance with the LiPA genotyping, detected 61% of all precancer and cancers, and 100% of cases associated to HPV16/18. In addition, it showed very high specificity highlighting its potential to be used to triage HPV positive women.